Solubility of the silver nitrate in supercritical carbon dioxide with ethanol and ethylene glycol as double cosolvents: Experimental determination and correlation

Solubility of the silver nitrate in the supercritical carbon dioxide containing ethanol and ethylene glycol as double cosolvents was measured under certain pressure and temperature range(10–25 MPa, 323.15–333.15 K). The impact of the pressure and temperature on the solubility was also investigated. Based on the experiment data,a correlation model concerning solid's solubility in supercritical fluids was established by combining the solubility parameter with the thermodynamic equation when a binary interaction parameter and a mixed solvent solubility parameter were defined. Experiments show the solubility of AgNO_3 increases with the pressure at a certain temperature. However, the influence of temperature is related to a pressure defined as the turnover pressure(12.3 MPa). When the pressure is higher(or lower) than this turnover pressure, silver nitrate's solubility shows increasing(or decreasing) trend as the temperature rises. Satisfactory accuracy of our presented model was revealed by comparing experimental data with calculated results.

Engineering Janus gold nanorod–titania heterostructures with enhanced photocatalytic antibacterial activity against multidrugresistant bacterial infection

Photocatalytic antibacterial approach shows great potential in treating multidrug-resistant bacterial infections.However,the bactericidal efficiency heavily depends on the photocatalytic activity of semiconductor materials,which is limited by the fast recombination of photogenerated electron–hole pairs.Janus nano-heterostructures with spatial control growth of TiO_(2)nanoparticles(NPs)at one end of gold nanorods(Au NRs)are designed via surface ligand regulation for photocatalytic sterilization and infected wound healing.The asymmetric nanostructure of Janus gold nanorod-titanium dioxide nanoparticles(Janus AuNR-TiO_(2) NPs)promotes the directional migration of charge carriers and is more conducive to the spatial separation of electron–hole pairs.Moreover,the injection of hot electrons and enhancement of plasmon near-fields from the surface plasmon resonance(SPR)effect further improve the photocatalytic efficiency of Janus AuNR-TiO_(2) NPs.Under simulated sunlight irradiation,large amounts of reactive oxygen species(ROS)are generated for photocatalytic antibacterial activity.Enhanced bactericidal efficiency up to 99.99%against methicillin-resistant Staphylococcus aureus(MRSA)is achieved in vitro.Furthermore,Janus AuNR-TiO_(2) NPs exhibit superior biocompatibility,structural stability,and also remarkably accelerate MRSA-infected wound healing.Taking the above all into consideration,Janus AuNR-TiO_(2) NPs,as an efficient antibacterial photocatalyst,offers a promising strategy for MRSA infectious therapy.

Molecular imaging:design mechanism and bioapplications

Molecular imaging is a non-invasive method to image and analyze the concentration and activity of functional biomolecules in cells or in vivo at molecular level,and plays an increasing role in deep understanding of biological processes,early and accurate diagnosis of diseases,and evaluation of treatment.Nowadays,numerous novel molecular imaging probes have been developed,involving every biomedical imaging modality,such as optical imaging,photoacoustic imaging,magnetic resonance imaging,single-photon-emission computed tomography,and positron emission tomography.In this review,we summarize the development of current state-of-the-art molecular imaging probes.We introduce the design strategies of molecular probes and detailed imaging modalities,and highlight the properties of probes and biomedical imaging applications in cells and in vivo,including disease diagnosis,drug tracking,and imaging-guided surgery.Then we discuss the perspectives and challenges in this emerging field.We expect this review could inspire more effective molecular imaging probes to be developed,achieving the goal towards clinical practices.

Special Topic:Near-infrared Ⅰ/Ⅱ Theranostics

Owing to the development of material science,nanotechnology and optical imaging techniques,theranostic agents that can be excited by near-infraredⅠ/Ⅱ(NIRⅠ/Ⅱ;NIRⅠ,λ=700-900 nm;NIRⅡ,λ=1000-1700 nm)light and/or emit fluorescence within these ranges are gaining momentum in the biomedical field.Compared to ultraviolet and visible light,the use of excitation light sources or fluorescent emissions in the NIRⅠ/Ⅱwindows holds several advantages.

Emerging low-dimensional black phosphorus:from physical-optical properties to biomedical applications

Low-dimensional black phosphorus(BP)is a class of nanomaterial derived from layered semiconductor BP which has gained tremendous attention in a variety of fields,owing to its uncommon structural features and appealing physical properties.More surprisingly,it has addressed current biomedical obstacles due to its orthorhombic puckered honeycomb crystal structure and unique properties such as tunable direct-bandgap,high carrier mobility,and exceptional photo-responsiveness.However,few reviews have focused on the interactions of low-dimensional BP’s physical properties with its biomedical performances.Herein,we discuss the physical properties of low-dimensional BP and potential biomedical applications associated with these physical properties.Moreover,different preparation methods,surface modification techniques,and future challenges,as well as future outlooks,are presented.This comprehensive review will provide a clear understanding of the relationship between lowdimensional BP’s physical properties and biomedical performances,with the ultimate goal of better knowledge of utilizing BP.

Dual activated NIR-Ⅱ fluorescence and photoacoustic imaging-guided cancer chemo-radiotherapy using hybrid plasmonic-fluorescent assemblies

Multimodal imaging in the second near-infrared window(NIR-II)guided cancer therapy is a highly precise and efficient cancer theranostic strategy.However,it is still a challenge to develop activated NIR-II optical imaging and therapy agents.In this study,we develop a pH-responsive hybrid plasmonic-fluorescent vesicle by self-assembly of amphiphilic plasmonic nanogapped gold nanorod(AuNNR)and fluorescent down-conversion nanoparticles(DCNP)(AuNNR-DCNP Ve),showing remarkable and activated NIR-II fluorescence(FL)/NIR-II photoacoustic(PA)imaging performances.The hybrid vesicle also exhibited superior loading capacity of doxorubicin as a superior drug carrier and efficient radiosensitizer for X-ray-induced radiotherapy.Interestingly,the accumulated hybrid AuNNR-DCNP Ve in the tumor resulted in a recovery of NIR-II FL imaging signal and a variation in NIR-II PA imaging signal.Dual activated NIR-II PA and FL imaging of the hybrid vesicle could trace drug release and precisely guided cancer radiotherapy to ultimately reduce the side effects to healthy tissue.

Plasmonic anisotropic gold nanorods:Preparation and biomedical applications

Gold nanorods(AuNRs)have attracted tremendous interest in biomedical fields due to their unique optical properties,tunable surface plasmon,and excellent biocompatibility.Their biomedical applications are mainly influenced by near-infrared(NIR)light,which can guarantee deep penetration into human tissues with minimal loss.However,traditional single AuNRs are unable to carry medicine into the lesion regions.Furthermore,it is difficult for AuNR nanoparticles to be implemented in multimodal imagingguided synergetic therapy,which has limited the application of AuNRs in the field of theranostics.In recent years,researchers have made great strides in modifying gold nanorods into nanomaterials for the integration of diagnosis and treatment.After modifying different functionalized shells on the outsides of AuNRs,heterostructure AuNRs known as anisotropic gold nanorod(AAuNR)nanoparticles possessed bioimaging and cancer therapy abilities,as well as a variety of other amazing biomedical applications.In addition,AAuNR nanoparticles can combine biomedical imaging and therapy into one system to achieve multimodal bioimaging guided synergetic therapy.In this study,we presented a current review of the latest progress of different types of AAuNRs nanoparticles and their biomedical applications.Furthermore,the challenges and future development trends of AAuNR nanoparticles in the biomedical fields are discussed.

Ultrasound-propelled Janus Au NR-mSiO_(2) nanomotor for NIR-II photoacoustic imaging guided sonodynamic-gas therapy of large tumors

Varieties of contrast agents have been developed for photoacoustic(PA)and ultrasound(US)imaging of cancers in vivo.However,access of traditional contrast agents into the sites of tumors has been principally through passive infiltration without any external force,preventing their deep penetration into the tissues of the tumors,and hindering the use of PA and US for deep tumor imaging.The concept of micro/nanomotors has been the focus of increasing attention as active theranostic agents due to their active movement in particular fluids,thereby conducting assigned tasks.Herein,US-propelled Janus mesoporous SiO_(2)partially coated gold nanorods(Au NR-mSiO_(2))were fabricated for deep tumor NIR-II PA imaging and synergistic sonodynamic-gas therapy.Following US irradiation,2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride(AIPH)loaded in mSiO_(2)(Au NR-mSiO_(2)/AIPH)generated N_(2)microbubbles with high efficiency to achieve nanomotor drive.Due to the deep penetration of US,the nanomotors exhibited a capability to travel deep within sites of tumors,providing enhanced PA/US imaging inside the tumors.Furthermore,the nanomotor based cancer therapy was demonstrated through synergistic N_(2)gas and sonodynamic therapy.The US-propelled nanomotors demonstrated a novel strategy for the simultaneous PA/US dual imaging deep within tumor tissues and precise therapy of large tumors.

An Activatable Near-Infrared Molecular Chemiluminescence Probe for Visualization of NQO1 Activity In Vivo

Chemiluminescence(CL)is a promising tool for diagnostics and sensing due to its inherent excitation light-free.However,most CL probes emit exclusively visible light with limited penetration depth,hindering their broad application for in vivo deep tissue imaging.This work reports an activated unimolecular CL probe(CL-P)that emits light in the near-infrared(NIR)region allowing a superior real-time visualization and detection of NAD(P)H quinone oxidoreductase 1(NQO1)in vivo.The NQO1-specific trimethyl-locked quinone is a lock for masking the NQO1 trigger site,and it was conjugated on the NIR Schaap's dioxetane chemiluminophore,achieving not only a subtle signal-to-noise ratio even at a depth of 15 mm in the chicken breast tissues,but also sensitively detecting the positive expression of NQO1 in A549 cells.CL-P has been successfully used for visualizing the aberrantly expressed NQO1 in subcutaneous xenograft A549 tumors.To our knowledge,this is the first work reporting the detection of NQO1 activity in the NIR region by unimolecular CL mode.Overall,the NQO1-activated visualization platform provides a guideline to transform a unimolecular CL sensor into a licensed imaging agent for the in vivo detection of enzyme-related diseases.

Activatable nanoscale metal-organic framework for ratiometric photoacoustic imaging of hydrogen sulfide and orthotopic colorectal cancer in vivo

Nanoscale metal-organic frameworks(nano MOFs)have emerged as a promising biomedical nanoplatform because of their unique properties.However,the exploration of nano MOFs in photoacoustic(PA)imaging is still limited.Here,a novel hydrogen sulfide(H2 S)-activated nano copper-based MOF(Cu-MOF)was developed as a near-infrared(NIR)ratiometric PA probe for in vivo monitoring of endogenous H2 S level and orthotopic colorectal cancer imaging via in situ reaction of nano Cu-MOFs with endogenous H2 S that is closely associated with tumor growth and proliferation in colon cancer.The synthesized nano Cu-MOFs displayed excellent PA responsiveness towards tumor H2 S level with high selectivity and rapid kinetics.The result suggests the developed probe may provide a unique opportunity to investigate the malignant behaviors of H2 S-associated events in vivo.

Mesoporous radiosensitized nanoprobe for enhanced NIR-Ⅱ photoacoustic imaging-guided accurate radio-chemotherapy

Oxygen deficiency is a major obstacle to hypoxic-related cancer theranostics,and developing the oxygen production nanoplatforms received the widespread attention.However,it is remaining a challenge to structure a nanoplatform with hypoxia alleviation effect and imaging-guided cancer radiotherapy.Herein,we present a novel theranostics nanoplatform(Au NPs/UCNPs/WO_(3)@C)comprising of tungsten trioxide(WO3)that loaded gold nanoparticles(Au NPs)and up-conversion nanoparticles(UCNPs)for improved photoacoustic(PA)imaging performance in the second near infrared window(NIR-Ⅱ,900-1,700 nm).Au NPs/UCNPs/WO_(3)@C exhibited superior oxygen-generation effect and doxorubicin loading capacity,thus serving as an efficient radiosensitizer for radio-chemo anti-cancer therapy.Importantly,the accumulated Au NPs/UCNPs/WO_(3)@C in the tumor region led to the increased NIR-Ⅱ PA imaging signal and the blood oxygen saturation signal,which could enhance radiation sensitivity and accurately guiding cancer radiotherapy to reduce side effects on normal tissues.This study with proof-of-concept confirmed the multifaceted characteristics and encouraging potential of biomimetic Au NPs/UCNPs/WO_(3)@C for NIR-Ⅱ PA imaging-guided tumor therapeutics.

X-ray sensitive high-Z metal nanocrystals for cancer imaging and therapy

Radiotherapy(RT)based on X-ray irradiation is a widely applied cancer treatment strategy in the clinic.However,treating cancer based on RT alone usually results in insufficient radiation energy deposition,which inevitably has serious side effects on healthy parts of the body.Interestingly,high atomic number(high-Z)metal nanocrystals as X-ray sensitizers can reduce the radiation dose effectively due to their high X-ray absorption,which has attracted increased attention in recent years.High-Z metal nanocrystals produce Auger and photoelectrons electrons under X-ray irradiation,which could generate large amounts of reactive oxygen species,and induce cellular damages.The sensitization effect of high-Z metal nanocrystals is closely related with their composition,morphologies,and size,which would strongly impact their performances in the application of cancer imaging and therapy.In this review,we summarize diverse types of X-ray sensitizers such as bismuth,hafnium,gold,and gadolinium for cancer RT and imaging applications.In addition,current challenges and the outlook of RT based on high-Z metal nanocrystals are also discussed.

Building Block Symmetry Relegation Induces Mesopore and Abundant Open-Metal Sites in Metal-Organic Frameworks for Cancer Therapy

The judicious choice of metal clusters and organic building blocks leads to a wide variety of structures for metal–organic frameworks(MOFs).In this work,we demonstrated that relegating the symmetry of a building block can also lead to the proliferation of new MOF structures.Herein,a triangle building block was elongated with reduced symmetry for MOF construction,which gave rise to a novel(3,4,6)-connected idp(based on the definition of Reticular Chemistry Structure Resource,http://rcsr.net/)network(PFC-16)with mesopores and abundant open-metal sites.The framework is composed of the rarely observed tetrakis hexahedral cages,surrounding which are small cages arranged in sodalite topology.The relegated symmetry was required for this novel self-assembly.The obtained MOF with mesopores,a robust backbone,and abundant open-metal sites can incorporate functional species in the structure,which is representatively demonstrated by internalizing the photosensitizer zinc(II)phthalocyanine(ZnPc)and the modifying tumor-targeting molecule folic acid(FA)in PFC-16.The obtained composite FA-ZnPc@nano-PFC-16 shows excellent photodynamic therapy(PDT)efficiency for both in vitro and in vivo experiments,representing a promising candidate for cancer therapy.